1. Field
An aspect of the present invention relates to a protection tape for sealing a sealing portion of a flexible outer casing and a secondary battery having the protection tape.
2. Description of the Related Art
In general, a lithium polymer battery is a representative secondary battery using a flexible outer casing. The lithium polymer battery refers to a battery in which a separator is interposed between positive and negative electrode plates. Hereinafter, a stacked structure of the positive and negative electrode plates and the separator is referred to as an electrode assembly. The separator performs not only the function of separating the positive and negative electrode plates from each other but also the function of a medium (i.e., an electrolyte). The separator is formed of a gel-type polymer electrolyte. The separator may be prepared in the state that a polymer is impregnated with an electrolyte so as to enhance ion conductivity.
A pouch is used as a representative flexible outer casing. After the pouch is disposed to surround an electrode assembly, its edge may be sealed using a method such as hot press. By using a flexible outer casing, the thickness of a secondary battery may be remarkably decreased as compared with that of a secondary battery using a metal can. However, the size of an electrode assembly in the same volume may be increased. That is, the capacity of a secondary battery per unit volume may be increased.